update $text mongo intexing -- Ngram?

[devincowan]

@ergjustin has found this bug when implementing users filters as in:
https://github.com/DendraScience/dendra-web-ui/blob/dev-justin/src/components/UsersSearch.vue#L199

$regex: "${escapeRegExp(search)}"

[devincowan]

We thought we needed to create a mongo text index for email full_name and name but turns out there already was one

appDb.users.createIndex(
      {
        email: 'text',
        full_name: 'text',
        name: 'text'
      },
      {
        name: 'text_index'
      }
    );

[devincowan]

so we decided to leave our regex searches as is for now and we will implement a better (Ngram?) search later

Implement n-grams for partial full-text search! https://en.wikipedia.org/wiki/N-gram